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Oct. 30, 1956 L. PETERLIK ET AL METHOD AND APPARATUS FOR STARTING INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet 1 Filed June 25, 1954 IN V EN TORS LEOPaLb PETERL K By [-DMOA/D UHER Oct. 30, 1956 L. PETERLIK ET AL 2,769,100

METHOD AND APPARATUS FDR STARTING INTERNAL COMBUSTION ENGINES Filed June 25, 1954 4 Sheets-Sheet 2 INV EN TORS Oct. 30, 1956 L. PETERLIK ET AL 2,769,100

METHOD AND APPARATUS FOR STARTING INTERNAL COMBUSTION ENGINES 4 Sheets-Sheet 3 Filed June 25, 1954 INVENTOR5 LEoPpl-D PETER L/K 4 Sheetsg-Sheet 4 Oct. 30, 1956 L. PETERLIK ET AL METHOD AND APPARATUS FOR STARTING INTERNAL COMBUSTION ENGINES Filed June 23, 1954 Fig. 6

IN V EN T0R,

LEOPal-D PETER L/K BY foMm/o C/Ha United States Patent METHOD AND APPARATUS FOR STARTING INTERNAL COMBUSTION ENGINES Leopold Peterlik, Vienna, Austria, and Edmond Uher, Cap dAntibes, France Application June 23, 1954, Serial No. 438,710

Claims priority, application Austria June 26, 1953 13 Claims. (Cl. 29038) The present invention relates to a new and improved method and apparatus for starting internal combustion engines.

More particularly, the present invention relates to a new and improved flywheel starter motor and starting arrangement.

At the present time there are at least two conventional methods for starting internal combustion engines, one being the flywheel starter motor and dynamo assembly, and the second being the dynastarter. The conventional flywheel starter unit operates by initially disengaging the flywheel from the engine shaft. The starter motor is then energized to drive the flywheel until a high kinetic energy is stored therein. The flywheel is then coupled to the engine shaft and simultaneously decoupled from the starter motor. The kinetic energy of the flywheel is then used to turn the engine shaft until the engine starts. In this type of system it is apparent that only the kinetic energy of the flywheel is used for rotating the engine shaft. Since the initial starting torque is very high for internal combustion engines, it is apparent that this kinetic energy may easily be used up before the en ine actually starts. It is apparent that at low temperatures this problem is materially increased.

The conventional dynastarter technique includes a motor permanently connected to the engine shaft. In order to overcome this high initial starting torque the motor is made oversize. Obviously, this is uneconomical under normal conditions when the engine is running.

The present invention stores kinetic energy in a flywheel disengaged from the engine shaft and then couples the flywheel to the shaft. However, the starting motor also remains coupled to the flywheel and engine shaft so that both its torque and the kinetic energy of the flywheel are simultaneously applied. This permits a decreased drain on the battery used to operate the starting motor as will be illustrated herein below.

Accordingly, it is an object of the present invention to provide a new and improved method and apparatus for starting internal combustion engines.

Another object is to provide a new and improved starting apparatus for internal combustion engines which operates more efficiently than presently known devices.

Still another object of the present invention is to provide a novel starting motor for internal combustion engines.

An object of the present invention is to provide new and improved starting apparatus which is automatically stopped after a time period independent of the starting of the internal combustion engine.

With the above objects in view, the present invention mainly consists of a starting apparatus which includes an electric starter motor having a rotatable armature. Flywheel means are connected to the rotatable armature to be rotatable therewith. Coupling means are included for connecting the armature and flywheel to the shaft of a combustion engine and for decoupling them therefrom, Whenever required, Means for energizing the motor and rotating the armature together with the flywheel, whenever required, are provided whereby for starting of the combustion engine, the motor is energized without coupling the armature to the engine shaft until the armature together with the flywheel attains a relatively high speed, storing substantial kinetic energy, whereupon the armature and flywheel are coupled to the engine shaft thus partly using the stored kinetic energy for rotation of the engine shaft and starting of the engine.

The novel features which are considered as characteristic for the invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings, in which:

Fig. 1 is a diagram showing the variation of current in the starting motor with time for both conventional starting units and starting units incorporating the present in vention;

Fig. 2 is a transverse cross sectional view of a starting motor capable of being used with apparatus incorporating the present invention;

Fig. 3 is a diagrammatic representation of the starting circuit;

Pig. 4 is a diagrammatic representation of automatic control means for terminating the starting cycle of the present invention when the current drawn by the motor exceeds a predetermined value;

Fig. 5 is a diagrammatic representation of an automatic control means for terminating the starting cycle which is dependent upon the surrounding temperature;

Fig. 6 is a diagrammatic representation of automatic control means including a mechanical escapement mechanism for terminating the starting cycle after a predetermined time interval; and

Fig. 7 is a diagrammatic representation of an automatic control means including a mechanical interlock and an electromagnetic relay for terminating the starting cycle when a predetermined value of current is reached.

Referring now to Fig. 1 a current-time diagram is illustrated with current in amperes plotted as the ordinate and time in seconds plotted as the abscissa. The heavy line, I, represents the variation of current in the conventional dynastarter unit. As indicated above this unit is permanently connected to the shaft of the internal combustion engine. Therefore, at the beginning of the starting cycle (time line A) a high current peak is drawn from the battery used to energize the starting motor. This is due to the high starting torque needed to overcome the inherent inertia of the starter unit and the engine.

This high current peak is maintained until the engine starts to turn over which, in the example shown, occurs in about 2 /2 seconds. At this point the current starts to decrease rapidly until after about 5 seconds (time line B) only the turnover torque of the engine itself must be overcome. As the speed of rotation increases the current decreases until a constant value is reached equal to the starting speed of the engine crank shaft. This constant current value is maintained until ignition takes place. When the engine starts the current consumption of the starter motor decreases and finally reaches zero unless the motor is disconnected from the current-source.

If ignition of the engine does not occur the motor speed will decrease after a certain time due to a drop in the battery supply voltage. This increases the our rent consumption and is illustrated in Fig. l by the line 1'. Obviously, it is possible under certain circumstances to continue operating the starting button until the battery is completely run down without the internal combustion engine ever being started.

The current-time relationship of apparatus incorporating the present invention is illustrated in Fig. 1 by the dotted line II. At the beginning of the starting cycle the starter motor and flywheel are disconnected from the engine shaft so that the motor need only overcome the load of the uncoupled flywheel. Therefore, at time zero (time line C) a substantially smaller current peak is produced than was necessary for the previous conventional case. As the flywheel starts to rotate the current consumption of the starter motor falls off until the time line A is reached. At this instant, in accordance with the starting method of the present invention, the flywheel and starting motor are coupled to the engine shaft. A slight increase in current consumption occurs at this point due to the starting torque needed for initiation of engine shaft rotation. It should be noted that the peak of the starting current is here much lower than the previous peak due to the use of the kinetic energy stored in the rotating flywheel.

As before, when the engine shaft starts rotating the current decreases until the constant starting speed of the engine crank shaft is reached. The starting cycle continues until the engine ignites, indicated by the decreasing line 2 or the engine fails to ignite the current increases in accordance with line 2.

In comparing the figures shown for the two starting arrangements, it is seen that for a 30 second starting period the convention arrangement consumes a total of 0.57 ampere hour. On the other hand, apparatus incorporating the present invention consumes only 0.21 ampere hour for a 30 second starting period. Accordingly, is apparent that starting arrangements incorporating the present invention may be made substantially smaller than conventional starters thereby providing considerable savings in cost of material.

Referring now to Fig. 2 a cross sectional view of one starter motor capable of being used with the present invention is shown. The motor is mounted within a motor housing 2d. In the housing, a shaft 192 is rotatably mounted by means of bearings S. An armature 2a is affixed to the shaft 192. On the inner surface of the housing 2.4 is mounted a series field winding 25 and a field winding 20. FiXedly mounted on the rotating armature is a flywheel 3 having a conicaliy-shaped enter 3 is a clutch lining Th3. Ring 4 is urged against lining 1% by a resilient member 5a attached to a shaft hub 4b. Hub 4b is mounted on the internal combustion engine shaft 40. Lever means 6, shown in diagrammatic form, are operable against the annular ring t in the direction indicated by the arrows 1454 to overcome the force of resilient member 4a. Lever means 6, in turn, are remotely operable by members 6:: and 6b.

in operation therefore the flywheel 3 and the armature 2:: may be decoupled from, the engine shaft ia by operating the lever 6 in the direction shown. Armature 2a is therefore free to rotate except for the starting inertia introduced by its own weight and the weight of the flywheel. At any desired time lever 6 may be operated to connect the rotating armature and flywheel to the engine shaft 4c. The operation of the starting motor illust d in Fig. 2 will be described hereiube'low.

Refe ring now to Fig. 3 the starting motor is shown diagrammatically in conjunction with the remainder of the starting apparatus. Power for the apparatus is provided by the storage battery 111. The positive terminal of battery H1 is connected to the terminal +A by a conductor 112. through a manually operable switch 7. Terminal +A is connected to one side of the series'field windings 2b. The other side of the windings 2b being connected to the terminal +D. The terminal +D is connected to the positive terminal of the armature 2a by a conductor 1.13; the negative terminal of armature 2a being connected to ground. Terminal +D is also connected by a conductor 114 to terminal of a conventional voltage regulator indicated by the dotted line 1c. Attached to terminal 115 is a biasing resistor 34, and current coils 3S and 36. The other side of coil 35 is connected to ground and the other side of coil 36 is connected to one of a pair of contacts 33. The other contact 33 is connected to battery ill by a conductor H6. Contacts 33 are normally open and may be closed by the magnetic field acting on core 37 and established by suflicient current flowing through the coil 36. Similarly, coil 35 is operable on contacts 32 by means of core 33.

The other side of the resistor 34 is connected to a terminal +F by means of a conductor 117. This terminal is also connected to one side of the shunt field windings 2c, the other side of these windings being connected on conductor 118 to one of a pair of normally closed contacts 8. The other contact 3 is connected to ground. Contacts 8 form part of a switch 119 which may be operated by lever 6a. Lever 6a, in turn, may be operated by lever 61) which itself is manually operable.

in operation, therefore, lever 61) is depressed to disconnect the armature and flywhel from the engine shaft. This also opens switch 119 thereby disconnecting the shunt field windings 20. Switch 7 is now manually operated to send current through the field windings 2b and the armature 2a in series. This initiates rotation of the armature 2a which quicky reaches high speed due to its connection as a series motor. This is the period between time lines C and A of Fig. 1. When the desired speed is reached lever 61) is released connecting the armature and flywheel to the engine shaft and simultaneously closing the switch 119. This is the part of the time cycle indicated by the time line A of Fig. 1. Due to the sudden introduction of the stored kinetic energy of the flywheel 3 a supplementary force is available to rotate the engine shaft in addition to the torque still provided by the starter motor. Because of the conical clutch arrangement illustrated in Fig. 2, the connection between the engine shaft and the flywheel is made with the smallest possible slip.

It should also be noted that when the starter switch 7 is o erated current flows through coil 35 attracting core 38 thereto and closing contacts 3.2. Therefore, when switch 11% is closed the windings 2c are connected in parallel with the rotating armature 2a. This provides an additional magnetic field in which the armature rotates thereby providing the additional starting torque available with compound operation. Therefore, by keeping switch 7 closed the engine shaft can be made to rotate at its constant ignition speed until the engine ignites. When the combustion engine starts the current consumption of the starter motor will decrease to Zero. If the engine does not start the motor will continue to draw current until the battery voltage decreases with a resultant rise in current to the point a on line 2' of Fig. 1.

In the above described method of operation the length of time during which the flywheel and motor are uncoupled from the engine shaft is determined only by the operator starting the engine. This is advantageous since the flywheel may be made to store additionalkinetic energy by longer decoupled operation. In lower temperatures it is known that the starting torque of the engine is much higher due to the thickness of the oil in the bearings and cylinders. Therefore the individual operator may determine the length of time for this uncoupled operation depending on the extraneous temperature conditions.

In'the embodiment shown in Fig. 3 it is possible by continuous operation of switch 7 to rotate the combustion engine until the battery 111 is exhausted. However, by means of the circuit arrangements described below, it

is possible to automatically deenergize the starter motor after a time period independent of the starting of the combustion engine.

Referring now to Fig. 4 one embodiment for automatically terminating the energization of the starting motor is shown. Only the automatic circuit elements are illustrated in Fig. 4, the remainder of the parts remaining as illustrated in Fig. 3. In place of the starter switch 7, a switch indicated by the arrow 121 is provided. Switch 121 is maintained in the normally open position by a compression spring 13 acting against the abutment 12. The remainder of switch 121 includes a rod 10, a winding about a magnetic core 9, contacts 14 and a contact closing element 11. One of the contacts 14 is connected to the positive terminal of the battery 111 by a conductor 122. The other contact 14 is connected to one side of coils 15, 16 and 16. The other side of coil 16 is connected to the armature 2a so that coil 16 is in series with this armature. The other side of coil 16 is connected to auxiliary contacts 39 and 40 and thereby to ground when these contacts are closed.

The other side of the winding 15 is connected to a movable armature 19 on which is mounted a contact 23. Contact 23 mates with grounded contact and is held in the normally closed position by means of spring 21 and adjustable set screw 22. The remainder of the relay about which coil 16 is wound includes the core 17 and the yoke 18.

In operation depression of the lever 6b raises lever 6a closing switch 121 against the pressure of the spring 13. As before, this also opens switch 119. Current is supplied from the battery to the armature on conductor 122 through switch 121 and coil 16. The contacts 20 and 23 are maintained closed by the spring 21 which is adjusted to overcome the force of the magnetic field set up by the coil 16 as long as the current through the coil 16 goes no higher than the value indicated at time line C of Fig. 1. Therefore, winding 15 is connected to ground and is energized to hold the magnetic core 9 in its displaced position, maintaining switch 121 closed. Now, if lever 6b is released this will close switch 119 but will not have the effect of opening switch 121.

Under these circumstances if the engine does not start within a certain time period, the current drawn by the armature 2a will increase to the point a of Fig. 1. As soon as the current exceeds this point the magnetic force set up by coil 16 will overcome the spring 21, opening the contacts 20 and 23. This will deenergize the holding winding 15 thereby opening switch 121. In the event that the engine starts before point a is reached the current through the armature will decrease toward zero. By this time the shunt field windings have been connected in parallel and the machine being rotated by the combustion engine, now acts as a generator. The generated voltage causes the coil 36 of Fig. 3 to close contacts 33, 39 and 40 of Fig. 4. This sends current through the auxiliary 16 providing enough magnetic force to open contacts 20 and 23 and release holding winding 15.

Therefore, with the above described arrangement we have provided means for automatically deenergizing the rotating motor after a time period, regardless of whether or not the engine starts. In the above case the period is ended when the current through the motor reaches a predetermined value.

Referring now to Fig. 5 a second automatic arrangement is shown for deenergizing the rotating motor at the end of a time period. The parts of Fig. 5 bearing the same numbers as parts of Fig. 4 have similiar functions. However, in place of the windings 16 and 16', a thermally operated switch indicated generally by the arrow 123 is provided. The switch includes a heater winding 25 and a bi-metallic spring 24. One side of the heater winding 25 is connected to ground through normally closed contacts 26 and 26'.

The switch 121 also includes a switch rod 10 through the center of its shaft 10. When the lever 61: is raised,

closing the switch 121, the switch rod 10' is raised opening the contacts 26, 26'. When the lever 6a is released the switch 121 remains closed due to the action of the holding coil 15. However, the switch rod 10 drops, thereby closing contacts 26, 26'. Current now flows through the heater winding 25 heating the bi-metallic element 24 until it bends suificiently to separate contacts 20 and 23. This opens the circuit of the holding coil 15 and opens switch 121.

Therefore, in the embodiment of Fig. 5 the rotating motor is automatically deenergized by means of the thermally controlled switch 123. One obvious advantage of such a thermal device is that heater 25 will take longer to reach the opening temperature when the surrounding temperature is low, that is, the lower the temperature, the longer will the circuit operate to start the engine.

Referring now to Figs 6 a mechanical escapement mechanism 31 is shown in place of the switch 123 of Fig. 5. Here the lever 6a closes the switch 121 which now winds the mechanism 31 in the direction of the arrow a by means of the switch rod 10 and the lever 29. When the escapement mechanism is wound the rod 28 is displaced from the lever 27 containing contact 23. This permits contacts 23 and 20 to close connecting winding 15 to ground to hold switch 121 in the closed position.

When the lever 6a is released, the switch 121 remains closed but the switch rod 10 is lowered and the escapement mechanism 31 unwinds until the rod 28 bears on the lever 27 and opens contacts 20 and 23. This opens the circuit of the holding winding 15 and opens switch 121. Therefore, in the above described embodiment the time interval 15 is controlled by the setting of the escapement mechanism.

Referring now to Fig. 7 another means for automatically terminating the energization of the motor is shown. In this arrangement a purely mechanical blocking is provided for holding switch 121 in a closed position.

On the shaft 113 of the switch 121 is mounted a hook 41 which is urged by a spring 42 against a fixed pin 43. Associated with the switch 121 is an auxiliary relay indicated generally by the arrow 124. This relay includes a core 45 surrounded by winding 16 and auxiliary winding 16. A push rod 45, made of a magnetic material, projects through the core 45 contacting a spring 46 at one end and the hook 41 at its other end.

In operation, closing of the switch 121 slides the hook 41 up over the horizontal push rod 45'. Upon release of the actuating lever 6a the shaft 10 of the switch 121 is prevented from moving downward by the engagement of push rod 45' with hook 41. The spring 46 bearing on rod 45' keeps this rod and hook 41 in positive engagement. The relay windings 16 and 16' are connected in the same manner as discussed for Fig. 4. Therefore if after a period of time the engine does not start, current through the winding 16 will increase to a point where the magnetic push rod 45 will be horizontally displaced against the action of the spring 46, releasing hook 41 and opening switch 121. Therefore in the above arrangement an automatic deenergization means is provided wherein the switch is mechanically locked and electrically opened when the current through the motor reaches a predetermined value.

It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of starting devices differing from the types described above.

While the invention has been illustrated and described as embodied in a starting apparatus for an internal combustion engine, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.

Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can by applying current knowledge readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention and, therefore, such adaptations should and are intended to be comprehended within the meaning and range of equivalence of the following claims.

What is claimed as new and desired to be secured by Letters Patent is:

'1. Apparatus for starting an internal combustion engine comprising, in combination, an electric starter motor having a rotatable armature; flywheel means fixedly connected to said rotatable armature; coupling means for connecting said armature and said flywheel to the shaft of a combustion engine and for decoupling them therefrom, whenever required; a first field winding arranged in series with said armature; first actuating means for energizing said first field winding, whenever required; a second field winding arranged in parallel with said armature; and second actuating means for energizing said second field winding, whenever required, whereby for starting of the combustion engine said first field winding is energized by said first actuating means without coupling said armature to the engine shaft until said armature together with said flywheel attains a relatively high speed, storing substantial kinetic energy, whereupon said second field winding is energized by said second actuating means and said armature and flywheel are coupled to said engine shaft.

2. A starting motor for internal combustion engines which comprises in combination, a motor housing; a first and a second field winding mounted on the inner surface of said housing; a shaft rotatably mounted in said housing; an armature aflixed to said shaft in operable association to said field windings; a flywheel fixedly mounted on said armature; an annular ring positioned adjacent the outer surface of said flywheel; resilient means for urging said annular ring against said flywheel, said resilient means being connected to both said annular ring and the shaft of said engine; and means for urging said annular ring away from said flywheel.

3. A starting motor for internal combustion engines which comprises, in combination, a motor housing; a first and a second field winding mounted on the inner surface of said housing; a shaft rotatably mounted in said housing; an armature aflixed to said shaft in operable association to said field windings; a flywheel fixedly mounted on said armature; said flywheel having an outer conical surface; a clutch lining attached to the outer surface of said flywheel; a conically shaped annular ring arranged adjacent said brake lining; resilient means for urging said annular ring againstsaid flywheel, said resilient means being connected to both said annular ring and shaft of said engine; and means for urging said annular ring away from said flywheel.

4. The method of starting internal combustion engines which comprises disengaging the shaft of said engine from the starting motor; energizing said starting motor.

in series operation until it acquires the desired kinetic energy; and coupling said starting motor to said engine shaft while simultaneously connecting said motor in compound operation until said engine starts.

5. The method of starting internal combustion engines which comprises disengaging the shaft of said engine from the starting motor; energizing said starting motor in series operation until it acquires the desired kinetic energy; coupling said starting motor to said engine shaft; and deener izing said motor after a time period independentofthe starting of said engine.

6. A method of starting internal combustion engines which comprises disenga ing the shaft of said engine from the starting motor; energizing said starting motor in series operation until it acquires the desired kinetic energy; coupling said starting motor to said engine-shaft; simultaneously connecting said motor in compound p la c: ation; and operating 'the starting motor as a generator after the engine starts.

'7. Apparatus for starting an internal combustion engine comprising, in combination, a motor housing; a series field windingumounted on the inner'surface of said housing; a shunt field winding also mounted on the inner surface of said housing; a shaft rotatably mounted in said housing; an armature affixed to said shunt "in operable association to said field windings; a flywheel fixedly mounted on said armature; an-annular ring arranged adjacent the outer surface of said flywheel; resilient meansfor urging said annular ringagainst said flywheel, saidresilientmeans being connected to both said annular ring and the shaft of said engine; manually operable lever means for urging said annular ring away from said flywheel; means for energizing said field windings and thereby rotating said armature together 'with said flywheel, whenever required, whereby for starting of the combustion engine saidlever'means is operated to urge said annular ring away from said flywheel; and said first field winding is simultaneously energized to rotate said armature and said flywheel until they attaina relatively high speed, storing substantial kinetic energy, whereupon said lever means is operated to permit contact-between said annular ring and said flywheel thus partly using the stored kineticenergy for rotation of the engine shaft and starting of the engine.

'8. Apparatus for starting an internal combustion engine, -comprising incombination, an electric starter motor having a rotatable armature, a series field winding and a shunt field winding; first actuating means for energizing said series field winding, whenever required; second actuating means for energizing said shunt field winding, whenever'required; flywheel means fixedly connected to said rotatable armature; coupling means 'for connectingsa'id armature and said flywheel to the shaft of a combustionengine and for decoupling 'them therefrom, whenever required, whereby for starting of the combustion engine said first actuating means energizes said series field winding to energize said motor as a series Imotor with said flywheel and said rotatable armature being decoupled from the engine shaft until said armature together with said flywheel attains a relatively high speed, storing substantial kinetic energy, whereupon said flywheel is rapidly coupled to said engine shaft and said second actuating means simultaneously energizes said shunt field winding to operate said motor as a compound motor thereby using the stored kinetic energy as well as thecompound motor for rotation of the engine shaft; and means for automatically deenergizing said field windings of said motor after'a time period independent of the starting of said engine.

9. The apparatus of claim 8 wherein said automatic deenergization means includes a relay for disconnecting said motorenergizing means when the current through said motor reaches a predetermined value.

10. Apparatus of claim 8 wherein "said automatic deenergization meansincludes a thermally controlled switch for disconnecting said motor energization means.

"11. Apparatus of claim 8 wherein said automatic deenergization means includes a switch operated by a mechanical escapement mechanism for disconnecting said motor energization means after a predetermined time interval.

12. Apparatus of claim 8 wherein said automatic defirst actuating means for winding, whenever required; flywheel means fixedly connected to said rotatable armature; coupling means for connecting said armature and said flywheel to the shaft of a combustion engine and for decoupling them therefrom, whenever required, whereby for starting of the combustion engine said first actuating means energizes said series field winding to energize said motor as a series motor with said flywheel and said rotatable armature being decoupled from the engine shaft until said armature together with said flywheel attains a relatively high speed, storing substantial kinetic energy, whereupon said flywheel is rapidly coupled to said engine shaft and said second actuating means simultaneously energizes said shunt field winding to operate said motor as a compound motor thereby using the stored kinetic energy as Well as the compound motor for rotation of the engine shaft; and means for automatically deenergizing said series field windings of said motor after said internal combustion engine starts.

References Cited in the file of this patent UNITED STATES PATENTS 1,056,417 Hodgkinson Mar. 18, 1913 1,139,210 Mitchell May 11, 1915 1,207,821 Wadsworth Dec. 12, 1916 1,217,244 Turbayne Feb. 27, 1917 1,419,607 Bowman et a1 June 13, 1922 1,511,491 Aspden Oct. 14, 1924 2,302,315 Hall Nov. 17, 1942 2,319,469 Nardone May 18, 1943 2,349,867 Heintz May 30, 1944 2,668,914 Uher Feb. 9, 1954 2,689,310 Kaufman Sept. 14, 1954 

